Engine starter



Nov. Z9, 1927. 1,650,637

w. L. McGRATH ENGINE STARTER Filed Nov. 5. 1925 Z5 ZO 3 Sheets-Sheet 2 WInc/emr i 'm //Wfm ENGINE STARTER Filed Nov. 5. 1923 Nov. 29, 1927.

the pinion in disengaged WILLIAM L. MCGRTH, OF ELMIRA, NEW YORK,ASSIGNOR T0 .ECLIPSE .MACHINE COMPANY, F ELMIRA, NEW YORK, A CORPORATION0F NEW YORK.

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Application led November 5, 1923. Serial No. 672,910. l

My invention has relation to means for starting or cranking an enginesuch as an internal combustion engine, and more particularly to thatpart of the engine starter system known as the drive or transmissionwhich transmits the power of the prime mover such as an electric motorto a member of the engine `to be started such as the flywheel thereof,such drive being capable of manual operation for engagement with theengine member and of automatic disengagement therefrom when the engineoperates under its own power. ln the practice of my invention, a drivingmember such as a pinion which is adapted to engage or mesh with theengine member cooperates with a spring adapted, to hold such pinion in anormal position upon its shaft and the object of my invention is toprovide .means whereby the so pressure or tension of thisspring may bevaried according to the different relative positions of the pinion onits shaft, in particular to lessen the tension of the spring at the timeof the disengagement of the pinion from the engine member or fly-Wheelwhen" there should be substantially no resistance encountered by thepinion in its longitudinal movement for that purpose, and tov increasethe tension of such spring against therpinion when disengaged and heldin retracted position on its shaftso as to insure the return of thepinion to its normal position.

ln the drawings, Figure 1 is an elevationv partly in section of theengine starter system embodying my invention and showing the parts intheir normal or disengaged posit-ion; Fig. 2 a View similar toFig. 1'but illustrating Jthe parts in engaged position; Fig. 3 a view similarto Fig. 2 but showing osition and the manual shift mechanism sti l inoperated or shifted position; Fig. la view similar to Fig. 1 exceptthatthe pinion is shown at its innermost position justbefore its shaft has rbeen returned to normal position to release suchl `pinion from itsretained position shown; Fig. 5 a longitudinal section of the parts asshown in Fig. 1; Fig. 6 a detailed view of the part of the shaftorsleeve; Fig. 7 a view of one endof the pinion; Fig. 8 a cross sectionof the pinion on the lines 8-8 of Fig. 7 Fig 9 a sectional elevation onthe line 9-9 of Fig. 5; Fig. 10 a sectional elevation of a startersystem embodying a Mmodiedforin of construction; Fig 1,1 a de-` tailedview of the` shaft and the spring retainer; Fig. 12 alongitudinalsection of the shaft.

For the purpose of a clear and definite disclosure of my invention, Ihave shown the 'same embodied in two different constructions of diive,one being illustrated in Figs. 1 tol 9 and the other in Figs. 1() to 12,but it will be understood that such invention may be embodied instructures of somewhat` different formation and arrangement, Withoutdeparting from the spirit and scope of my invention. It will also beunderstood that while I have shown my invention incorporated in aso-called outboard type of drive and also in the direct type of drive,the same may be incorporated in the nboard type and also in the indirecttype of drive.

Referring to the particular embodiment of my invention as illustrated inFigs. 1 to 9, the priine mover is an electric motor 1 which is providedwith an 'extended armature shaft 2 having a suitable bearing 3 at itsouter end. This motor is provided with a suit-able switch and the usualelectrical connections (not shown) which are preferably actuated by themanual or pedal shift connections hereinafter described.

Upon the driving or armature shaft 2, there is mounted a hollow shaft orsleeve 4 for rotary [movement with 'the armature shaft and forlongitudinal movement thereon. Thishollow shaft may be made in one pieceor in two pieces as shown in Fig) 5, with one piece provided with ascrew threaded portion 5. As shown, this sleeve which may be termed ascrew-shaft, is splined to the armature shaft by meansV of thecooperating splines 6 which are indicated more clearly in Figs. 5 and12. The screw-shaft is provi ed at its inner end withthe parallelcollars or flanges? as either separate or integral parts which flangesform an intervening circumferential groove 8 .with which cooperates therollers 9 of suitable shifting means.

Such shifting means are here shown as a of a pinion 12 adapted to meshwith the teethl of the flywheel v13 and threaded upon the sleeve -orscrew-shaft. This pinion' is normally positioned at the outer end of thescrew-shaft and against the stop nut 14 as shown in Fig. 1, and is heldin this normal position by means of the coil spring 15 which eneirclesthe screw shaft and normally bears against the inner face of the pinionor against an interposed spring abutment 16. The object of my presentinvention is to provide means whereby this spring is capable ofimparting to the pinion different degrees of pressure or tensionaccording to the different periods in the cycle of operation, that isaccording to the different relative positions of the pinion upon itsscrew-shaft and of the screw-shaft upon the armature shaft.

To this end, the armature Shaft is provided with a suitable abutment forthe inner end of the spring, such abutment here consisting of az pin 17extending transversely of the armature shaft and passing throughlongitudinal slots 18 in the sleeve 4 and extending therebeyond at bothends. Such abutment also comprises a flanged plate 19 having a centralopening whereby it slips upon the sleeve and having a circumferentialgroove 20 to receive the innermost coil of the spring. This plate issuitably shaped as shown in order to keep the pin in place, suoli pinbeing removable for dis-assembly purposes. This plate is held againstthe pin 17 in all the different longitudinal positions of the sleeve asshown by Figs. 1 to 5.

A cup or drum 21 is secured to the sleeve and thereby moves in unisontherewith, the pring 15 at its inner end encircling such rum. Withinthis drum, there is pivoted in the slot 22 of the screw-shaft andupon'the pivot pin 23 a latch 24 whose outer end is adapted to engage anotch 25 in the inner end of the bore of the pinion to thereby hold suchpinion in a retracted position such as shown in Figs. 3 and 4. Thislatch is spring pressed to operative position by means of the coilspring 26 interposed between the inner end of the latch and the interiorof the drum 21. In the inoperative position shown in Fig. 5, such innerend of the latch bears against the periphery 27 of thearmature shaft butwhen the sleeve is moved outwardly along the armature shaft such end ofthe latch is forced downwardly by the spring pressure and slides downthe sloping shoulder 28 and upon the reduced portion of the armatureshaft between the splines and the outer end of the latch is movedupwardly. The latch is thereupon in osition for engagement with thepinion w enever the latter comes within its range. This retainingmechanism per se forms no part of my present invention, but is concernedtherewith because it occasions one of the conditions or positions of thepinion-which is taken care of by the spring 15.

Describing a cycle of operation of my engine starter system andbeginning with the parts in their normal position shown in Fig. 1, whenthe operator actuates the shifting means the drive assembly is shiftedlongitudinal] along the armature shaft to the position s iown in Fig. 2,at which time the cur rent is supplied to the starting motor 7 eitherautomatically as an incident to the actuation of the shifting means orby a separate operation. The spring 15 which had been under somecompression in its normal position shown in Fig. 1 now expands to theposition shown in Fig. 2, at which time it exerts practically'noresistance or pressure upon the pinion. The drive parts are now incranking position and when the engine has been cranked and operatesunder its own power, the pinion will be automatically demeshed due tothe fact that the pinion is screw threaded upon its shaft.

Immediately upon the starting of the engine, the operator should releasethe shifting means which will be returned in the usual way t0 normalposition and the pinion will be demeshed by reason of its screw actionupon its shaft, but in the event 'that he does not do so, the parts willthereupon be in the relative position shown in Fig. 3 in which thepinion is shown ldemeslied from the flywheel, but engaged by the hitch.

Fig. 4 shows the positions just before the final return movement of thesleeve is completed. This final return movement causes the inner end ofthe latch 24 to ride up the slope 28 and upon the periphery 27 of thearmature shaft, thereby withdrawing such latch from the pinion andpermitting the latter to move spiially to normal position as shown inFigs. 1 and 5. In the position shown in Fig. 4, the spring 15 becomescompressed and such presure is utilized in forcing the pinion to movespirally to normal position in the manner described inasmuch as thescrew threads have a comparatively long lead.

Thus means al'e provided for varying the tension of the spring 15according to different phases of the cycle of operation to thereb exertdifferent pressures upon the pinion. Vghen the parts are in the relativeposition shown in Fig. 4, at which time the pinion rcquires its maximumamount of spring pressure, the tension of the spring is at maximum..When, however, the pinion is in mesh with the flywheel and is about tohe demeshed` as shown in Fig. 2, the spring presl sure thereupon is thenat a minimum, inasmuch as the spring tension is at a minimum orpractically nothing. Therefore. the demeshing of the pinion is notinterfered with by the spring and the spring is permitted to exertsufficient pressure upon the pinion at the proper time to insure itsreturn to normal position as shown inv Figs. 1 and The pinion is heldout of engagement with the flywheel regardless of the englnes operloulll-3 Leeoeav ation and of the operators carelessness in not restoringthe parts underhis control to normal position. Moreover, the engagementof the pinion with the flywheel cannot be reestablished until after thecompletion of the cycle above described. The spring must be of suthcienttension to edectively restore the pinion to its normal position againstthe stop nut but the samemust not interfere with the throwout of thepinion in the demeshing opcraton or prevent sufiicient longitudinalmovement of the pinion to enable the pinion to be caught by the latch.Consequently, my novel means provides the requisite spring tensionagainst the pinion for restoring it to normal position and a minimum orpractically no tension at the initiation of the throwout of the pinion.

ln Figs. 10 and 1l I have shown a modied form of construction wherebythe length of the drive is considerably reduced, The particular lengthof the drive of Figs. l to 9 is dependent upon the length of the slots18. ln order to shorten the drive, l attain, in the modified structure,the proper slot length by providing similar slots in both the armatureshaft and in the sleeve. Accordingly, the armature shaft is providedwith a longitudinal slot 29 at one end of which the transverse vpinion17 is located, and the sleeve with the longitudinal slots 30, such slots29 and 30 being in alignment as shown in Fig. 1l. lln other respects,the construction andoperation are the same as that hereinbeforedescribed.

lido not herein broadly claim the construction and the arrangement ofthedrive including the longitudinally shiftable sleeve or driving member orpinion thereon and the catch device for holding the pinion' in demeshedposition while the screw shaft or sleeve is still shifted -to crankingposition as the sume represent subject matter of my prior applicationsfor patent including application filed on January d, 1923, Serial No.I610,672, the present applicationbeing directed to theparticularu'nvention pointed out in the claims herein.

l claim :Y n

1. An engine starter drive including a longitudinally slidable rotatableshaft, a driving member mounted thereon for rotary movement therewithand `for longitudinal movement thereof, and yielding means acting on thedriving member tending to hold it to anormal position on the shaftl andacting with a variable degree of pressure according to the longitudinalposition of the shaft and with the least pressure in cranking position.c

2. An engine starter drive including a rotatable and longitudinallyslidable shaft, a driving member mounted thereon for rotary movementtherewith and for `longitudinal movement'thcreof, and yielding means Atobe started when such engine starts on its own power, and yielding meanscooperating with the driving member and tending to hold it to a normalposition on the shaft With a variable tension but with the least tensionwhen about to be disengaged from the engine member. l

4.1km engine starter drive including a longitudinally slidable rotatableshaft. a

driving member mounted thereon for rotary movement therewith and forlongitudinal lmovement thereof, a stop means on the shaft, and ayielding means cooperating with the driving member and tending to holdit in normal position against the wstop means and acting with a variabledegree of pressure according to the longitudinalposition of the shaftand with the least pressure 1n cranking position.

5. An engine starter drive including a longitudinallyk slidablerotatable shaft, ay

driving member mounted thereon for rotary movement therewith and forlongitudinal -movement thereof, and a spring cooperating with thedriving member and tending to hold it in a normal position on the shaftand acting with a variable degree of pressure according to thelongitudinal position of the shaft and with the least pressure incranking position.

6. An engine starter drive including a longitudinally sli'dablerotatable shaft, a driving member' mounted thereon for rotary movementtherewith and for longitudinal movement thereof, a stop means on theshaft, and a coiled spring encircling the shaft and cooperating with thedriving member and tending to hold it in a normal position against thestop means and acting with a variable degree of pressure according tothe longitudinal position of the shaft and' with `the leastpressure incranking position.

7. An engine starter drive including a longitudinally slidableIrotatable shaft mounted for rotary and longitudinal movement, a drivingmember mounted thereon `for rotary movement therewith and longitudinalmovement thereof, and adapted to engage a member of the engine to bestarted, and a yielding means cooperating with the driving member andtending to hold it in a normal position on the shaft, such yieldingmeans being constructed and arranged ico fill

titl

driving member mounted on the. hollow shaft for longitudinal movementthereof and rotary movement therewith, a pin extending transversely ofthe driving shaft, said hollow shaft having longitudinal' ,sl-otsthrough `which the pin extends, and a spring bearing at one end againstsaid pin and at the other end against the driving member.

19. An engine starter drive including` a rotatable driving shaft, ahollow shaft mounted thereon for longitudinal movement thereof androtary movement therewith, a driving member mounted on the hollow shaftfor longitudinal movement `thereof and rotary movement therewith` saiddriving shaft having a radial projectioi'i and said hollow shaft havinga longitudinal slot through which such projection extends` a springabutment connected with said projectionand a spring bearing at one endagainst the abutment and at the other end againstthe driving member.

20. An engine starter drive-imfluding a rotatable driving shaft, ahollow shaft mounted thereon for longitudinal movement thereof androtary movement therewitl'i, a driving member mounted on the hollowshaft for longitudinal movement thereof and rotary movement therewith,said two shafts having pin and slot connection, and a spring connectingbetween the pin and driving member.

2l. An engine starter drive including a rotatable shaft, a drivingmember mounted thereon for rotary movementtherewith and for longitudinalmovement thereof, means for holding the driving member in a retractedposition on the shaft, and yielding means acting on the driving membertending to hold it to a normal position on the shaft, and acting with avariable degree of pressure.

22. An engine starter drive including a rotatable shaft, av drivingmember mounted thereon for rotary movement', therewith and forlongitudinal movement thereof to engage a member of the engine tobestarted, a stop means on the shaft, means on the shaft for engaging thedriving member in its longitudinal movement after disengagement from theengine member and for holding it in .retracted position away from thestop means, and yielding means acting on the drivingr member tending tohold it to a normal position against such stop means, the vdegree ofpressure of such yielding means being varied.

23. An engine starter drive including a screw shaft, a pinion threadedthereon for rotary movement therewith and for longitudinal movementthereof, into engagement with a'member of the engine to be started, astop on the shaft against which stop the pinion is normally positioned,means on the shaft for holding the driving member in retracted positionon the shaft after disengagementfrom the engine member, and a springnormally pressing the pinion against the stop, the degree .of pressureof such spring being varied.

E24. An engine starter drive including a rotatable driving shaft` ahollow shaft ,mounted thereon for longitudinal movement thereof androtary movement therewith, a driving member mounted on the hollow shaftfor longitudinal movement thereof and rotary movement t-herewith,manually operated means for bodily shift-ing theliollow shaft anddriving member longitudinally of the driving shaft, means for holdingthe driving member in a. disengaged position before the hollow shaft isreturned to normal position, and a spring carried by the driving shaftand cooperating with the driving member to exert a tension thereondependent upon the relative positions of the hollow shaft and drivingmember.

25. An engine starter drive including a. rotatable driving shaft, ahollow shaft mounted thereon for longitudinal movement thereof androtary movement therewitli,'a

' driving member mounted on thehollow shaft for longitudinal movementthereof and rotary movement therewith. manually operated means forbodily shift-ing the hollow shaft and driving member longitudinally ofthe driving shaft, means for holding the driving -member in a disengagedposition before the hollow shaft is returned to normal position, a drumsecured to the hollow shaft and extending over said holding means, and aspring carried by the driving shaft and extending over said drum andbearing against the driving member.

26. An engine starter drive including a rotatable driving shaft, ahollow Shaft mounted thereon for longitudinal movement thereof androtary movement therewith, a driving member mounted on the hollow shaftfor longitudinal movement thereof and rotary movement therewith,manually operated means for bodily shifting the hollow shaft and drivingmember longitudinally of the driving shaft, means for holding thedriving member in a disengaged position before the hollow shaft isreturned to normal position, said holding means comprising a latchpivoted on the hollow shaft and adapted to engage the driving member, aspring tending to force the latch to engaging position, a drum securedto the hollow shaft and extending over the latch, said spring beinginterposed between the drum and the latch, and a spring connected at oneend to the driving shaft and bearing at its other end against thedriving member.

27. An engine starter drive including a rotatable driving shaft, ahollow screw shaft splined thereon for longitudinal movement thereof androtary movement therewith, a pinion threaded on the screw shaft, saidscrew shaft having a stop at one end, and a spring connected at one endto thel driving shaft and cooperating with the pinion to normally holdit against such stop.

28. An engine starter drive including a rotatable driving shaft, ahollow screw shaft splined thereon for longitudinal movement thereof androtary movement therewith, a pinion threaded on the screw shaft. saidscrew shaft having a stop at one end, and a coiled spring encircling thescrew shalt and connected at one end to the driving shaft and bearing atits other end against the pinion.

29. An engine starter drive including a rotatable driving shaft., a.hollow screw shaft splined thereon for longitudinal movement thereof androtary movement therewith, a pinion threaded on the screw shaft. saidscrew shaft having a stop at one end. said driving shaft having aprojection and said screw shaft having a longitudinal slot through whichsuch projection extends, and a spring connected at one end to saidprojection and bearing at its other end against the pinion.

30. An engine starter drive including a longitudinally slidablerotatable shaft having a stop at one end, a driving member mounted onthe shaft for rotary movement therewith and longitudinal movementthereof, means for moving the driving member longitudinall)v todisengage it from a member of the engine to be started when the latterbecomes the driver, and yielding means cooperating with the drivingmember to normally hold the same against said stop and acting on suchdriving member with a pressure which varies according to the position ofthe driving member on the shaft.

31. An engine starter drive inehuling a longitudinally slidable'rotatable shaft having a stop at one end. a driving member mounted onthe shaft for-rotary movement therewith and longitudinal movementthereot', and a spring cooperating with the driving member to normallyhold the same against said stop, whereby the tension ot' the spring isvaried according to the longitudinal position of such shaft.

32. An engine starter drive including :L central rotatable drivingshaft, a sleeve mounted on such shaft to slide longitudinally thereonand to be driven thereby. :i driving member mounted on the sleeve l'orrotary movement therewith and for longitudinal n'iovement thereof, andyielding means acting on the driving member tending to hold it to anormal position on the sleeve and acting with a variable degree ot'pressure according to the longitudinal position ot such sleeve upon itsshatt and with the least pressure in cranking position.

32). An engine starter drive including a central rotatable drivingshaft, a screw threaded sleeve mounted on such sbatt to slidelongitudinally thereon and to be driven thereby, a driving memberthreaded on they sleeve for rotary movement therewith and forlongitudinal movement thereof, and yielding means acting on the drivingmember tending to hold it to a normal position on the sleeve and actingwith a variable degree of pressure according to the longitudinalposition ot such sleeve upon its sha it and with the least pressure incranking position.

VILLIAM L. MoGllAllI.

